1. Field of the Invention
The present invention relates to a method of reestablishing a radio link and a wireless communication device using the method, and more specifically, to a method of reestablishing a radio link in a wireless communication network using directional communication and a wireless communication device using the method.
2. Discussion of Related Art
In order to accommodate surging data traffic in next-generation mobile communication networks after long term evolution (LTE)/LTE-advanced (LTE-A), the use of a millimeter-wave band (30-300 GHz), which allows allocation of a wider frequency band, is considered. In the case of a millimeter-wave band, as compared to a microwave band (sub-6 GHz) of LTE/LTE-A, there is a characteristic of large path loss, and, accordingly, in order to reduce the large path loss in the millimeter-wave band, directional communication through beamforming and multi-antenna beamforming technologies is being considered so that existing cell coverage can be guaranteed.
A transmission node is connected in a network and performs directional communication with another transmission node. This means that transmission and reception are performed in one specific selected direction between the two transmission nodes, which means that the transmission beam and reception beam in a specific direction are used. Therefore, in the case of a radio link established between transmission nodes in a network using millimeter waves, sudden loss of radio link may occur due to blockage or the like, unlike an existing radio link.
In order to reestablish a radio link when loss of radio link occurs as described above, a procedure for determining each beam direction for transmission and reception between two transmission nodes is further required, unlike a procedure for reestablishing a radio link which uses an existing microwave band (<6 GHz). To this end, a beam search procedure must be performed.